Build it if you can get your hands on one. The Tenet Arca Plasmor is still a top-tier Steel Path primary heading into Update 43, and that bouncing plasma wave changes how you clear a room. Skip the Riven though. Disposition sits at 0.55, one of the lowest in the game, so that plat is better spent elsewhere.
The plasma wave ricochets off walls and floors, reportedly up to four bounces per shot, instead of dying on the first surface it hits. That’s the real upgrade over the base Arca Plasmor: it tags enemies around corners and in the next room over, not just whatever’s standing directly in front of you.
This is a Kuva-style weapon, so the number on the wiki isn’t the number you’ll get. Every copy comes off a Sister of Parvos with its own randomized damage bonus, roughly 25% to 60%, stacked on top of whatever element her Progenitor Warframe assigns it. Base stats before that bonus: 760 Radiation damage, 22% crit chance, a 2.0x crit multiplier, 34% status chance, 1.0 shots per second.
The pitch is an AoE shotgun with real range and a status ceiling high enough to make Galvanized Savvy hit hard. The catch is getting one at all.
How to get the Tenet Arca Plasmor
You can’t buy this one, and you can’t buy the base weapon either. The base Arca Plasmor is a Clan Dojo research project: unlock the blueprint in the Energy Lab (Lanka has to be researched first), then build it in the Foundry with Fieldron, Control Modules, Cryotic, credits, and 1 Forma. Build time is about a day. You need Mastery Rank 10 to equip it.
The Tenet version only drops from a Sister of Parvos who spawned already carrying an Arca Plasmor. You can check her loadout before committing. It shows up before you subdue her, so you’re not burning Requiem attempts on a Sister carrying a gun you don’t want. Work out her Requiem mod sequence, subdue her, then Vanquish her. Not convert. Converting makes her a crew member and you never see the weapon. Vanquishing drops it straight into your Foundry.
The listed Mastery requirement is 16, but that gate reportedly doesn’t apply to picking up Sister weapons in practice. Players report claiming Sister and Lich weapons well under the listed rank, as long as they find and vanquish the right one. If you’d rather trade for the setup than hunt it yourself, an un-vanquished Sister carrying the weapon can be traded through the Dojo’s Crimson Branch room. The finished, vanquished gun can’t be traded directly once it’s yours.
Once you have it, Valence Fusion (feeding it a duplicate) pushes the damage bonus toward the 60% cap. If the Progenitor element you ended up with is the wrong one, Elemental Vice lets you swap it without hunting down a whole new Sister.
Stats
| Class | Primary |
|---|---|
| Mastery Rank | 16 |
| Trigger | SEMI |
| Noise | Alarming |
| Fire Rate | 1 |
| Accuracy | 9.1 |
| Magazine | 10 |
| Reload | 3 s |
| Critical Chance | 22% |
| Critical Multiplier | 2x |
| Status Chance | 34% |
| Riven Disposition | (0.55) |
| Damage | 760 total |
|---|---|
| Radiation | 760 |
Riven disposition is 0.55, one pip out of five. That’s among the lowest in the game, so a Riven here is a weak return compared to almost any other primary you could roll one for instead.
Builds
This is a hybrid crit and status build leaning on the Galvanized mods’ on-kill triggers to snowball damage once a room gets going. Progenitor element matters as much as any single mod slot, since it sets your dominant status type. The highest-voted community build for this weapon (itwillsit’s, 726 votes on Overframe) runs a Magnetic Progenitor stacked with Cold, Viral, and Electricity procs, and specifically argues against a Toxin Progenitor for this setup. Toxic Barrage below is a flex slot: run it if Toxin fits what you’re fighting, swap it for whatever element matches your own Progenitor, or drop in a Riven if you’re willing to eat the low disposition.
Shotgun
Shotgun
Shotgun
Shotgun
Shotgun
Shotgun
Shotgun
Shotgun| Mod | Effect |
|---|---|
| Primed Ravage | +110% Critical Damage. |
| Critical Deceleration | +200% Critical Chance, -20% Fire Rate. |
| Primed Point Blank | +165% Damage. |
| Primed Chilling Grasp | +165% Cold damage. |
| Toxic Barrage | +60% Toxin damage, +60% Status Chance. |
| Galvanized Savvy | +80% Status Chance. On kill: +40% direct damage per status type affecting the target, for 20 seconds, stacks up to 2x. |
| Galvanized Hell | +110% Multishot. On kill: +30% more Multishot for 20 seconds, stacks up to 4x. |
| Galvanized Acceleration | +30% projectile speed and beam range. On kill: +30% more for 10 seconds, stacks up to 2x. |
Arcane slot: Primary Merciless, ranked to 5. It adds a flat 30% reload speed and buffs the whole magazine’s damage, and that damage buff grows as you land kills over the course of the mission. Both cross-checked build guides for this weapon settle on it independently.
Reviewed September 2026.
Pros and Cons
Pros
- Plasma wave bounces off surfaces, reportedly up to four times per shot, hitting angles and rooms the base Arca Plasmor’s straight blast never reaches
- Very high status and crit ceiling. Hybrid builds land 60% to 100%+ status chance with a 4x or better crit multiplier
- 36m damage falloff range, nearly double the base gun’s 20m, and stretchable further with Galvanized Acceleration
- Progenitor element plus Valence Fusion lets you pick its damage type instead of being stuck with one
- Its top Overframe build sits at 726 votes, and 2026-dated guides still rank it among the best Steel Path primaries
Cons
- Riven disposition is 0.55. Rivens for this weapon are a weak investment next to almost anything else
- Slower and less ammo-efficient than the base gun: 1.0 shots/sec versus 1.1, 3.0s reload versus 2.8s, 40 max ammo versus 50
- Getting one is entirely RNG-gated. You need a Sister carrying this exact weapon plus the correct Requiem sequence, with no direct purchase or crafting path for the Tenet version
- Pure Radiation damage, no physical split. Armor strip and physical procs have to come from your mod slots, not the weapon itself
This one’s for players who already have Steel Path unlocked and want a primary that clears crowds without a lot of babysitting. If you’re still early into hunting Sisters of Parvos, don’t go out of your way for this specific weapon. Treat it as a bonus when a loadout check happens to turn one up. Under Mastery Rank 10, you can’t even research the base gun yet, so there’s no rush either way.